For mobile, advertising is increasingly becoming about catching the consumer at the right place, if not the right time. Google’s $750M AdMob buy this month is undoubtedly supporting the case for numerous mobile marketing firms, especially in the eyes of VCs. 1020 Placecast, a San Francisco mobile advertising company, does just that. Their schtick is that they alert shoppers of special deals as they pass storefronts. That schtick just landed them $5M in a second round of funding. New investor Quatrex Capital joined for this round, with participation from previous backers Onset Ventures and Voyagers Capital.

Earlier this year, 1020 partnered with Alacatel-Lucent to launch a carrier-based opt-in mobile ad service in North America. By getting the go-ahead from a user to track their mobile searches and location, targeted ad delivery is not only possible, it’s getting the right message to the right person often at the the right time. What more could an advertiser or marketer ask for? Then again, customers may not know exactly what they’re agreeing to when accepting the terms, and stalkerish ads may still turn a consumer off to a brand. So 1020 Placecast’s clients and anyone working in the stalker-advertising space, as I like to call it, need to be careful.

1020 Placecast will be tested out with three retailers over the holidays, where consumers will be able to sign up for geo-targeted deals. 1020 Placecast doesn’t have pin-point accuracy yet, but if the consumer enters a “geo-fence” targeted area, they will get pinged.

For more information on “push” mobile advertising, check out this great writeup over at GigaOm from September’s Mobilize 09′ conference. The post quotes Balaji Natarajan, senior manager of mobile technologies for Capgemini as saying “it’s the transition from a reactive to proactive medium. Push is a relevant model, because the phone is an interruptive device.”